Unit 4: Cell Communication and Cell Cycle

Unit 4: Cell Communication and Cell Cycle Q&A

How do cells communicate with one another?

Cells can communicate through cytoplasmic junctions, direct contact, secretion of messenger molecules, and synapses.

What are hormones in the context of cell signaling?

Hormones are chemical messengers released by endocrine glands that create a cascade response in target cells.

What is transduction in a signal transduction pathway?

Transduction is the relaying and amplification of a signal inside the cell after reception.

What is the role of protein kinases in signal transduction?

Protein kinases are enzymes that add phosphate groups to proteins, changing their activity and participating in phosphorylation cascades.

What do protein phosphatases do?

Protein phosphatases are enzymes that remove phosphate groups from proteins, deactivating their activity and resetting the signaling process.

What are second messengers?

Second messengers amplify the signal that the cell receives.

How does cAMP function as a second messenger?

cAMP amplifies the signal inside the cell and helps the cell carry out its appropriate response.

What is homeostasis?

Homeostasis is the process of maintaining a stable internal environment.

What is the difference between a set point and a normal range in homeostasis?

A set point is a specific value the body tries to maintain, while a normal range is the acceptable variation around that set point.

How do lipid-soluble and lipid-insoluble hormones differ in their cellular response mechanisms?

Lipid-soluble hormones pass through the cell membrane and bind to intracellular receptors, while lipid-insoluble hormones bind to cell surface receptors.

What is cytokinesis?

Cytokinesis is the division of the cytoplasm, forming two daughter cells after mitosis.

What evidence indicates the control of the cell cycle through cytoplasmic signals?

Experiments showing the transfer of cytoplasm from cells in different cycle stages into cells at different stages demonstrate that cell cycle control is mediated by cytoplasmic signals.

What distinguishes benign tumors from malignant tumors?

Benign tumors are non-cancerous, grow slowly, and do not invade surrounding tissues, while malignant tumors are cancerous, grow rapidly, invade, and may metastasize.

What is metastasis?

Metastasis is the spread of cancer cells from the original primary tumor to other areas of the body, forming new secondary tumors.

What is the role of checkpoints in the cell cycle?

Checkpoints are control points in the cell cycle where the cell assesses if key processes have been completed correctly before proceeding.

Why is cancer considered a disease of the cell cycle?

Cancer involves uncontrolled cell division due to mutations disrupting the normal regulatory mechanisms of the cell cycle.

How do animals regulate energy storage?

Animals convert excess food into fat and use hormones like insulin and glucagon to balance energy storage and release.

What is negative feedback in homeostasis?

Negative feedback reduces or stops a process to maintain balance within the organism.

What is a signal transduction pathway?

A signal transduction pathway is a series of molecular events and reactions that leads to a cellular response following the reception of a signal.